Electrical sparking system



June 6, 1967 H, SEGALL ET AL ELECTRICAL SPAHKING SYSTEM Filed March 27, 1964 INVENTORS Lou/s H. SEGQLL 3,324,350 ELECTRICAL SYSTEM Louis H. Segall, Sidney, and irving E. Linlrronm, Hancock, N.Y., assignors to The Bendix orporation, Sidney, N.Y., a corporation of Deiaware Filed lvlar. 27, 1964, S91. N 355,165 18 Claims. ((11. 3152t 9) This invention relates to electric sparking systems and more particularly to certain improvements therein.

Electric sparking systems are utilized in various applications such as, for example, systems which per se are utilized to investigate the phenomenon of electric sparking, ignition systems, etc. Generally, in these systems, electric sparking occurs across a gap to which is applied electrical energy which causes ionization and breakdown of the gap and the consequent sparking thereat. It sometimes happens in the prior art system of the aforementioned kind that the gap is inoperable due to some mechanical or electrical failure at the gap or in the system. As a result the system is inoperable or in a somewhat hazardous condition due to the inability of the electrical energy to be discharged across the inoperable gap. Prior art systems devised to overcome these defects have not 'been entirely satisfactory for one reason or the other. The most satisfactory prior solution has been obtained by utilizing a safety gap connected in parallel with the sparking gap of the system. In such a system, the safety gap is adapted to be ionized and broken down and thus by-pass the sparking gap when the latter is inoperable. However, while the safety gap operates well and has been used to great extent, a more positive by-pass means is desirous to prevent premature by-passing of the sparking gap such as might result from high surging peak levels caused, for example, by transients or the like in the electrical systems and which thereby cause premature ionization and breakdown of the by-pass or safety gap. It is also possible to have .a more positive by-pass means that mitigates the possibility of becoming inoperable due to, for example, some mechanical or electrical failure in the system such as is the case in systems utilizing a safety gap as aforementioned when the safety gap might become inoperable due to, for example, electrical or mechanical failures that may or may not be also causing the sparking gap to be inoperable.

The invention, therefore, has among its objects the provision of an electrical sparking system having one or more sparking gaps that utilizes positive by-pass means for 'by-passing one or more inoperable sparking gaps thereof.

Another object of the invention is to provide an electrical sparking system, which is adapted to provide simultaneous sparks across at least two sparking gaps when both are operable, that utilizes positive by-pass means for the mutual exclusive by-passing of either gap that is inoperable so as to allow electric sparking to occur at the other gap.

Still another object of the invention is to provide an electrical sparking system of the last-mentioned kind, that further utilizes the positive by-pass means for by-passing both gaps when both are inoperable.

Still other objects of the invention are to provide an ignition sparking system utilizing the principles of this invention, and to provide electrical sparking systems that mitigate or eliminate the aforementioned, as well as other defects, of the prior art electrical sparking systems.

The above and further objects and novel features of the invention will more fully appear from the following description when the same is read in connection with the accompanying drawing. It is to 'be expressly understood, however, that the drawing is for the purpose of illustration only, and is not intended as a definition of the limits of the invention.

In the drawing, wherein like parts have been designated by the same reference characters,

FIG. 1 is a schematic diagram of an electrical sparking system of this invention illustrating one embodiment of an ignition sparking system of high voltage type; and

FIG. 2 is a schematic diagram of an electrical sparking system of the invention illustrating another embodiment thereof in an ignition sparking system of the low voltage type.

It is to be understood, that while the principles of the present invention are depicted in specific preferred embodiments thereof, that these principles are applicable to other types and kinds of electrical sparking systems, such as, for example, electrical sparking systems for investigating electrical sparking phenomena, as well as to single or multi-gap electrical sparking systems, or to multi-gap systems which provide for simultaneous or mutually exclusive operation, or combinations thereof, of the plural gaps thereof as will be obvious hereinafter to those skilled in the art.

Briefly, as illustrated in the drawing, a condenser means 10, FIG. 1, or the condenser system indicated generally by the reference character 10', FIG. 2, is adapted to be charged by a suitable energy source illustrated by the respective blocks formed by dash lines 11 or 11' of FIGS. 1 and 2, respectively. In the particular embodiments illustrated in FIGS. 1 and 2, the electrical sparking systems thereof are illustrated as dual gap ignition sparking systems such as the types utilized in certain jet engine ignitionsystems and thus each has two ignition gap devices 12, 13, FIG. 1, and 12', 13, FIG. 2, across the respective gaps of which electrical sparking for ignition purposes occurs. Coupling means, illustrated by the respective block formed by dash lines 14, FIG. 1 and 14', FIG. 2, are provided to discharge the condenser means across the respective dual gaps of each system when the condenser means is charged to a predetermined level. In the dual gap embodiments illustrated in FIGS. 1 and 2, if both gaps are operable, the condenser means is discharged across both igniter gaps via their common ground connections to provide ignition sparking simultaneously thereat. In the event either one of the gaps is inoperable due to, for example, an open circuit condition at one of the gaps, there are provided positive inductive by-pass means comprising, for example, saturable reactance indicator means coupled to each of the gaps of the system in a parallel coupling relationship. Thus, the inductive by-pass means are illustrated in FIG. 1 as saturable inductors 15, 16 having severable respective windings 17, 18 and cores 19, 20 and in FIG. 2 as two saturable inductors having two severable bifilar windings 21a-21b and 22a22b, respectively, mounted on a common core 23. Thus, in operation if, for example, one of the gaps were inoperable, the condenser means would discharge through the inductor connected in parallel with the particular inoperable gap and across the other gap, if operable, of the system via their common ground connection to provide ignition sparking thereat. The system is further adapted to discharge the condenser means through both of the inductors via their common ground connection should both of the gaps of the system be inoperable. The saturation time of each inductor is judiciously selected so that the impedance of the respective inductors remain relatively large for a time sufiicient to allow its associated gap, if operable, to break down before the inductor becomes saturated as will be explained hereinafter.

Referring now to FIG. 1 in greater detail, the source 11 is illustrated as comprising input terminals 24, 25 to which is connected a DC. supply, not shown, such as a Patented June 6, 1S5? battery or the like. A suitable R.F. filter, indicated generally by the reference character 26 and shown by way of example in FIG. 1 as comprising an R.F. filter of the ir type having condensers 27, 28 and inductor 29, is coupled to the input terminals via switching means 34}, 31. The output of RP. filter 26 is coupled to the input coil 32 of the transformer of a vibrator device, indicated generally by the reference numeral 33 and comprising stationary contact 34 which is connected to ground via condenser 35 and a normally closed vibrating or movable contact 36 which is also grounded. As is well known to those skilled in the art, when the switches 30, 31 are closed, the vibrator 33 is energized so as periodically to break the connection between contacts 34 and 36, the latter having a soft iron member 37 attached thereto which is adapted to be attracted by the coil 32 when the latter is energized. As a result, current pulses appear in the primary winding 38 of step-up transformer 39. The output of transformer 39 is rectified by a rectifier bank 40 which is connected to the transformer secondary winding 41 and charge condenser 10. A bleed-off resistor 42, connected across condenser 10, is provided to discharge condenser 10, such as when the system is rendered inoperative by the opening of switches 30, 31.

The means 14 of FIG. 1 comprises a dual gap control device 43 having a main gap between electrodes 44-45 and a control gap between electrodes 44-46 thereof. The control gap is adapted when it is broken down to ionize the main gap, and the device 43 may be of the type disclosed in Linkroum US. Patent No. 3,229,146. Briefly, the device, as disclosed therein, comprises a gas filled envelope having three spaced electrodes within the envelope forming a first main longer gap and a second shorter triggering or control gap. Upon discharge of the control gap, the gas between the electrodes forming the main gap becomes highly ionized and thus permits discharge of energy across the main gap. In FIG. 1, to ionize and breakdown the control gap of device 43, suitable means are provided and are illustrated in the embodiment of FIG. 1 as comprising a condenser 47 which is adapted to be charged by the source 11 and which is coupled to the control gap via the circuit comprising the upper side of condenser 47, conductors 48, 49, electrodes 44, 46, conductor 50, primary winding 51 of voltage step-up transformer 52, conductor 53 and the lower side of condenser 47. Other means for ionizing and breaking down the control gap of device 43 may also be utilized, including, if desired, for example, the modification of the embodiment of FIG. 1 such that condenser 10 is utilized to ionize and breakdown the control gap of device 43 so that it partially discharges thereacross. Thus, condenser 47 could be connected in lead and the right hand end of primary 51 could be tied to lead 76 and hence to secondary Winding 64, eliminating the necessity for leads 48 and 53. Condenser 10 could then partially discharge across control gap 44, 46 into the condenser inserted in lead 50 in series with primary winding 51.

In the preferred embodiment illustrated in FIG. 1, a high impedance resistor 54 in the charging circuit of condenser 47 is connected to the electrode 46 and condenser 10 via conductor 55 and is provided to prevent the substantial discharge of condenser 10 across the control gap of device 43 when this gap breaks down under control of condenser 47.

Condenser 10, when the igniter gaps of devices 12 and 13 are operable and the main gap of device 43 is thus ionized or broken down, is substantially discharged through the spark gaps of devices 12, 13 in the circuit comprising the upper side of condenser 10, conductors 56, 75, 49, electrodes 44, 45, conductor 57, a secondary winding 58 of voltage step-up transformer 59, conductor 60, the respective gaps of devices 12 and 13 and their commonly grounded connections 72, 74, conductor 61, the secondary winding 64 of transformer 52, conductors 76, 55, 62, 63 and the lower side of condenser 10.

In the embodiment illustrtaed in FIG. 1, the igniter gap of device 13 is ionized and broken down by a step-up voltage induced in the secondary winding 64 of step-up transfer 52 when condenser 47 is discharged across the control gap of device 43 and through primary winding 51. The igniter gap of device 12 is ionized and broken down by a step-up voltage induced in the secondary winding 58 of transformer 59 when condenser 10 is discharged partially in the circuit loop comprising conductors 56, 75, 49, the broken down main gap 4445 of device 43, the primary winding 65 of transformer 59, the condenser system comprising the parallel combination of condenser 66 and the branch of series connected condensers 67, 68 and their common grounded connection, conductors 69, 76, 55, 62, and 63. By judiciously selecting the values of condensers 66 to 68 to be low relative to the value of condenser 10, only a portion of the energy is dissipated in the last described circuit loop. In those cases where the condenser 10 is to be utilized to initiate the triggering action of the control gap 4446 of device 43, the circuit must be also modified appropriately so that the condenser 10 is connected to be partially discharged across the broken down control gap and through the primary winding 51 of transformer 52, as described above, to induce a step-up voltage across the igniter gap of device 13 for ionization and breakdown of the latter.

As aforementioned the saturable inductors 15 and 16 are effectively connected in shunt across the respective igniter gaps of devices 12 and 13. Thus, as seen in FIG. 1, the winding 17 of inductor 15 is connected in a series branch which also comprises the grounded connection 71 and the primary winding 65 of transformer 59. The last described series branch is in turn connected in parallel with a series branch comprising the secondary winding 58 of transformer 59, the igniter gap of device 12 and the latters grounded connection. In a series branch comprising winding 18 of inductor 16 and its grounded connection 73, the winding 18 is connected directly in parallel with a series branch comprising the secondary winding 64 of transformer 52, the igniter gap of device 13 and its grounded connection 74.

The system of FIG. 1 operates as follows:

When switches 30, 31 are closed, a series of rectified pulses appear at the output of source 11 thereby charging condenser 10 and condenser 47. The circuit loop for charging condenser 47 comprises conductors 75, 48, condenser 47, conductor 53, primary winding 51, conductor 50, resistor 54, and conductors 55, 62.

Condenser 47 charges at a rate relative to the rate at which condenser 10 is charged, and when the charge on condenser 10 reaches a predetermined level the charge on condenser 47 ionizes and breaks down the control gap of device 43. As a result two substantially simultaneous actions occur. In one action, condenser 47 is discharged via the circuit loop formed by conductors 48, 49, the broken down control gap of device 43, conductor 50, primary winding 51, and conductor 53. This results in the ionization of the igniter gap of device .13 via the step-up voltage induced in the secondary winding 64 as aforedescribed. In the other action, the breakdown of control gap 44, 46 triggers the main gap of device 43 causing condenser 10 to be partially discharged through the primary winding 65 in the manner aforedescribed and thereby ionize the gap of device 12. By judiciously selecting the aforesaid predetermined level of charge to be sufficiently high to cause breakdown of the gaps of devices 12 and 13, and if both gaps of the devices 12 and 13 are operable, the condenser 10 is then substantially discharged through the loop circuit comprising conductors 56, 75, 49, the main gap of device 43, conductor 57, secondary winding 58, conductor 60, the igniter gap of device 12, ground connections 72, 74, the igniter gap of device 13, conductor 61, secondary winding 64, and conductors 76, 55, 62, 63. In this manner, simultaneous ignition sparking occurs at the gaps of devices 12 and 13.

If, however, the igniter gap of device 12 is inoperable and cannot be ionized and broken down, the condenser is then substantially discharged through the loop circuit comprising conductors 56, 75, 49, the main gap 44, 45 of device 43, conductor 57, primary winding 65, inductor 15, grounded connections 71, 74, the igniter gap, if operable, of device 13, conductor 61, secondary winding 64, and conductors 76, 55, 62, 63. Under these conditions, the gap of igniter device 13 would provide thereat ignition sparkmg.

Should the ignition gap of device 12 be operable and that of device 13 inoperable, then the condenser 10 is substantially discharged through the loop circuit comprising conductors 56, 75, 49, the main gap of device 43, conductor 57, secondary winding 58, conductor 60, the igniter gap of device 12, grounded connections 72, 73, inductor 18, and conductors 69, 76, 55, 62, 63. Ignition sparking is thereby obtained at the gap of device 12 under these conditions.

Should both igniter gaps of devices 12 and 13 be inoperable, the system of FIG. 1 further provides for the substantial discharge of condenser 10 through the loop circuit comprising conductors 56, 75, 49, the :main gap of device 43, conductor 57, primary winding 65, inductor 15, grounded connections 71, 73, inductor 18, and conductors 69, 76, 55, 62, 63.

Referring now to FIG. 2, source 11' is illustrated as comprising an A.C. generator having an output winding 77 which is coupled to the primary winding of a step-up transformer 78, via the switch 79, lead 80, RF. filter 81 and common ground connections. The secondary winding 82 is coupled, via the rectifier indicated generally by the reference numeral 83, to the input of condenser system 10' and provides thereat rectified pulse signals that charge condenser system 10.

The means 14' comprises a control gap device 84 having a control gap between the electrodes 85 and 86. Electrode 85 is connected via the conductor 87 to one side of the output of condenser system 10'. The igniter gaps of ignition devices 12' and 13, illustrated in FIG. 2 by way of example as being of the shunted surface type, have one of their electrodes serially connected to each other via their grounded connections 88, 89. The other electrode of the igniter gap of device 12 is connected to electrode 86 of device 84 via conductor 90 and the other electrode of the igniter gap of device 13 is connected to the other side of the condenser system 10 via the conductor 91.

Connected in parallel with the igniter gap of device 12 is the winding 2111-21!) of the saturable inductor via the junction 92 and their respective grounded connections 88, 93. Likewise the winding 22a22b of saturable inductor is connected in parallel with the igniter gap 13 via the junction 94 and their respective grounded connections 89, 95.

In operation, when the switch 79 of FIG. 2 is closed, storage condenser system or means 10' is charged by the source 11. When the charge in the condenser means 10' reaches a predetermined level the control gap of device 84 ionizes and breaks down. If both igniter gaps of devices 12 and 13' are operable, condenser means 19' discharges around the loop circuit comprising conductor 87, the control gap of device 84, conductor 90, the igniter gaps of evices 12' and 13 and their ground connections 88, 89 in series and conductor 91, thereby causing simultaneous ignition sparking at the gaps. However, if the igniter gap of device 12' is inoperable and the igniter gap of device 13' is operable, then the condenser means 10' is discharged through a loop circuit comprising conductor 87, the control gap of device 84, conductors 90, 96, inductor windings Illa-21b, the ground connections 93, 89, the igniter gap of deivce 13 and hence providing ignition sparking thereat, and conductor 91. On the other hand, should the igniter gap of device 12 be operable and the one of device 13' inoperable, condenser means 10' is then discharged through a loop circuit comprising conductor 87, the control gap of device 84, conductor 90, the igniter gap of device 12' and hence providing ignition sparking thereat,

the grounded connections 88, 95, winding 22a-22b of the saturable inductor, and conductors 97, 91. Should both the igniter gaps of devices 12' and 13' be inoperable, the system of FIG. 2 further provides for the discharge of condenser means 10' via the loop circuit comprising conductor 87, the control gap of device 84, conductors 90, 96, the winding Zia-21b of inductor 23, the grounded con nections 93, 95, the other Winding 22a22b of inductor 23, and conductors 97, 91.

If it is desired to impress the full voltage of the storage condenser system 10' across each of gaps 13' and 12' in succession, a condenser 98 (not otherwise necessary) which is small in comparison to system 10' may be connected between lead and ground in shunt with gap 12' and hence in parallel with the even smaller distributed capacity of the gap 12. The full voltage of the storage condenser 10' will then be initially applied across gap 13 through the added small condenser 98 in series. The gap 13, thus ionized, will present small resistance or impedance and consequently the full voltage of the storage condenser Will be applied across gap 12' in series with ionized gap 13 and the condenser system will then dump its full charge through the gaps in series.

As previously explained, with normal igniter gap operation in the systems of FIGS. 1 and 2, the igniter gaps fire before any appreciable current can build up in the coil Winding inductance in parallel therewith. However, if one gap does not fire, current will build up in the corresponding coil, causing its core to saturate thus reducing its impedance and establishing a path for condenser discharge through the other gap.

The delay in current build-up to the point of saturation can be expressed in the following equation:

( BAN where T =time in seconds to core saturation B=fiux density in gauss for saturation A=cross section area in sq. cms. N number of turns Ezapplied voltage across the coil.

A satisfactory high tension ignition sparking circuit in accordance with the embodiment of FIG. 1 of the present invention employs circuit components having the following values and/or components:

Condenser 10, f. (approx.) 5 Resistor 42, megohms 20 Condensers 67, 68, ,uf. (approx.) each .05 Condenser 66, ,uf. (approx) 0.1

Maximum voltage applied to igniter gaps of devices 12, 13, DC. volts (approx.) each 28,000 Breakdown voltage of control gap of device 43,

DC. volts (approx.) 3050 Breakdown voltage of main gap of device 43,

DC. volts (approx.) 4500 Substituting the above values in Equation 1 when both gaps are operable:

2 14,000 .sosx 14s 10 T=.000008 sec. T==8 microseconds In the case where one igniter gap fires and the other doesnt, all the voltage, i.e. 3000 volts, approximately, is placed across one coil and T, the time as calculated above, approaches one-half the above value obtained or 4 micro seconds. However, with both igniter gaps operating, the high voltage ionizing pulse appears in less than 1 microsecond and the voltage across the coil decreases rapidly, thus increasing the saturation time to a value beyond the storage capacitor discharge time.

The time for saturation delay of the by-pass or crossover coil may be described as its volt-second characteristic. For the above described coil, the volt-second characteristic may be expressed as shown below:

(5) TE=BAN (6) TE=14,000 .605 148 10 (7) TE=.012 volt seconds A satisfactory low tension sparking circuit in accordance with the embodiment of FIG. 2 of the present invention employs circuit components having the following values and/or characteristics:

Condenser 10a, ,uf. (approx) 2 Condenser 10b, 10c, af. (approx.) each Maximum voltage applied to igniter gaps of devices 12', 13', DC. volts (approx) each 1750 Breakdown voltage of control gap of device 84,

DC. volts (approx) 3500 Condenser 98, t. (approx) .0005

Characteristics of saturable inductor:

Core 23-Arnold AH430, Hipersil, cross section /s" X 365'! Windings 21a21b35 turns, #25 wire Windings 22a-22b35 turns, #25 wire Inductance of windings 21a-2lb, or 22a22b:

Non-saturated-S millihenrys, approx. Saturated95 microhenrys, approx. Voltage applied across:

Windings 21a-21b and 22a22b, serially connected (both igniter gaps operable)1750 D.C. volts approx.) Winding 2111-2111, or 22a22b (when appropriate igniter gap not operating)3500 D.C. volts (approx.)

It is to be understood, that while the inductive by-pass means are preferably chosen to be saturable inductors in the systems of FIGS. 1 and 2, that other types of inductors, for example, an inductance with a ferrite core, may also be utilized. By judiciously selecting the rise time of the current in the type of inductor utilized to be longer than the time required for the gap with which it is associated, to breakdown in the system, the inductor will effectively by-pass the associated gap should the latter become inoperative.

Although only a limited number of embodiments of the invention have been illustrated in the accompanying drawing and described in the foregoing specification, it is to be expressly understood that various changes, such as in the relative parameters of the circuit elements, the materials used, and the like, as well as in the suggested manner of use of the apparatus of the invention, may be made without departing from the spirit and scope of the invention as will now be apparent to those skilled in the art.

What is claimed is:

1. An electrical sparking system comprising condenser means, means to charge said condenser means, a first gap device having a first gap associated therewith, a second gap device having a second gap associated therewith, means to couple said first and second gaps and said condenser means in a series coupling relationship to discharge 8 said condenser means across said first and second gaps in series to provide simultaneous sparks thereat, first inductor means coupled to said first gap in a parallel coupling relationship and adapted to bypass said first gap and discharge said condenser means through said first inductor means across said second gap in series therewith to provide a spark thereat when said first gap is inoperable, and second inductor means coupled to said second gap in a parallel coupling relationship and adapted to bypass said second gap and discharge said condenser means through said second inductor means and across said first gap in series therewith to provide a spark thereat when said second gap is inoperable.

2. An electrical sparking system according to claim 1 wherein said means to couple comprises a control gap for controlling the discharge of said condenser means.

3. An electrical sparking system according to claim 1 wherein said first and second inductor means are further adapted to discharge said condenser means through said first and second inductor means in series when said first and second gaps are both inoperable.

4. An electrical sparking system according to claim 1 wherein said first and second inductor means comprise first and second saturable reactors, respectively.

5. An electric sparking system comprising a storage condenser, a source of energy coupled to said storage condenser to charge the same, a first spark gap, a second spark gap, a spark discharge dual gap control device having a main gap and a control gap, first circuit means for coupling said condenser, said main gap, and said first and second spark gaps in a series coupling relationship, means for ionizing and breaking down said control gap to ionize said main gap when the charge on said condenser is at a predetermined level, second circuit means for coupling said control gap and said means for ionizing and breaking down said control gap and comprising therein means to ionize a predetermined one of said first and second spark gaps when said control gap is broken down, said first circuit means comprising therein means to ionize the other of said first and second spark gaps when said main gap is broken down, said condenser being discharged partially through said first circuit means across the broken down said main gap and through said means to ionize said other spark gap, and being further discharged across the serially connected first and second spark gaps to provide simultaneous sparks thereat when said first and second spark gaps are ionized, first inductor means coupled to said first spark gap in a parallel coupling relationship to by-pass said first spark gap and discharge said condenser through said first inductor means and across said second spark gap in series to provide a spark thereat when said first spark gap is inoperable, and second inductor means coupled to said second spark gap in a parallel coupling relationship to by-pass said second spark gap and discharge said condenser through said second inductor means and across said first spark gap in series to provide an ignition spark thereat when said second gap is inoperable.

6. A sparking system according to claim 5 wherein said first and second inductor means are further adapted to discharge said condenser through said first and second inductor means in series whenever said first and second spark gaps are both inoperable.

7. A sparking system according to claim 5 wherein said first and second inductor means comprise first and second saturable reactors, respectively.

8. An electrical sparking system comprising storage condenser means, a source of energy coupled to said condenser means to charge the same, a first igniter gap, a second igniter gap, a spark discharge control gap, means for coupling said control gap, said first and second igniter gaps and said condenser means in series coupling relationship, first inductor means coupled to said first igniter gap in parallel coupling relationship, second inductor means coupled to said second igniter gap in parallel coupling relationship, said condenser means when charged to a predetermined level being adapted to discharge across said control gap and said first and second igniter gaps to provide simultaneous sparks thereat, said condenser means when charged to said level being further adapted to discharge across said control gap and through said first inductor means and across said second igniter gap to provide a spark thereat when said first igniter gap is inoperable, and said condenser means when charged to said level being further adapted to discharge across said control gap and through said second inductor means and across said first igniter gap to provide .a spark thereat when said second igniter gap is inoperable.

9. A sparking system according to claim 8 wherein said condenser means when charged to said level is still further adapted to discharge across said control gap and through said first and second inductor means in series when said first and second igniter gaps are both inoperable.

10. An ignition sparking system according to claim 8 wherein said first and second inductor means comprise first and second saturable reactors, respectively.

11. In an ignition sparking system, condenser means, means to charge said condenser means, an igniter gap, means including a step-up transformer coupled to said condenser means for ionizing said gap, means to couple said igniter gap to said condenser means in series therewith to discharge said condenser means directly across said igniter gap when the latter is ionized to provide an ignition spark thereat, and saturable inductor means coupled to said igniter gap in parallel therewith to by-pass said igniter gap and discharge said condenser means through said inductor means when said igniter gap is inoperable to conduct the discharge before saturation of said inductor means.

12. An ignition sparking system as defined in claim 11 comprising a second igniter gap connected in series with the first-named igniter gap across said condenser means, and an inductor coupled to said second igniter gap to by-pass the latter when the same is inoperable without by-passing said first igniter gap.

13. An ignition system or the like comprising a source of electrical energy including a storage condenser, at least two igniter gaps, means for intermittently connecting said gaps in series across said source to discharge said condenser and create spark discharges across said gaps, and a saturable reactor connected in parallel with each of said gaps, the impedance of each of said reactors when not saturated being greater than the impedance of the gap connected in shunt therewith.

14. An ignition system or the like as defined in claim 13 wherein said reactors comprise saturable cores having substantially square hysteresis loop characteristics.

15. An electrical sparking system comprising storage condenser means, means for charging said condenser means, a normal discharge circuit connected across said condenser means comprising control gap means and two spark gaps connected in series, a first by-pass circuit branch comprising a saturable reactance inductor, said first branch being connected in parallel shunt with a portion of said normal discharge circuit, said portion including one of said spark gaps, and a second by-pass circuit branch comprising a saturable reactance inductor, said second branch being connected in parallel shunt with a portion of said normal discharge circuit, said last-named portion including the other of said spark gaps. Whereby when a normal discharge of said condenser means through said control gap means is incapable of bridging one of said spark gaps, said discharge will saturate and pass through the reactance inductor in the said circuit branch in parallel with said last-named one of said spark gaps and in series with the other said spark gap- 16. An electrical sparking system comprising storage condenser means, means for charging said condenser means, a spark gap, a discharge circuit for said condenser means comprising said spark gap, and saturable inductance means connected in parallel with a portion of said discharge circuit including said spark gap, said inductance means having greater impedance than said portion of the discharge circuit to the initial discharge of said condenser means, whereby said condenser means discharges normally across said spark gap and discharges through said inductance means only when said spark gap fails to conduct after a pre-determined time delay following initiation of the discharge.

17. An electrical sparking system as defined in claim 16, wherein said inductance means includes a saturable reactor having high impedance to the discharge of the condenser means prior to magnetic saturation thereof.

18. An electrical sparking system as defined in claim 16 comprising control gap means in the discharge circuit for controlling the discharging of the condenser means.

References Cited UNITED STATES PATENTS Re. 25,347 3/1963 Segall et al. 3l5209 2,254,882 9/1941 Blankenbuehler 315-122 2,835,785 5/1958 Williams 21969 2,896,123 7/1959 McNulty 315209 3,086,144 4/1963 Short 3 l5209 3,146,376 8/1964 Segall et al. 315209 JOHN W. HUCKERT, Primary Examiner.

D. O. KRAFT, Assistant Examiner. 

1. AN ELECTRICAL SPARKING SYSTEM COMPRISING CONDENSER MEANS, MEANS TO CHARGE SAID CONDENSER MEANS, A FIRST GAP DEVICE HAVING A FIRST GAP ASSOCIATED THEREWITH, A SECOND GAP DEVICE HAVING A SECOND GAP ASSOCIATED THEREWITH, MEANS TO COUPLE SAID FIRST AND SECOND GAPS AND SAID CONDENSER MEANS IN A SERIES COUPLING RELATIONSHIP TO DISCHARGE SAID CONDENSER MEANS ACROSS SAID FIRST AND SECOND GAPS IN SERIES TO PROVIDE SIMULTANEOUS SPARKS THEREAT, FIRST INDUCTOR MEANS COUPLED TO SAID FIRST GAP IN A PARALLEL COUPLING RELATIONSHIP AND ADAPTED TO BY-PASS SAID FIRST GAP AND DISCHARGE SAID CONDENSER MEANS THROUGH SAID FIRST INDUCTOR MEANS ACROSS SAID SECOND GAP IN SERIES THEREWITH TO PROVIDE A SPARK THEREAT WHEN SAID FIRST GAP IN INOPERABLE, AND SECOND INDUCTOR MEANS COUPLED TO SAID SECOND GAP IN A PARALLEL COUPLING RELATIONSHIP AND ADAPTED TO BYPASS SAID SECOND GAP AND DISCHARGE SAID CONDENSER MEANS THROUGH SAID SECOND INDUCTOR MEANS AND ACROSS SAID FIRST GAP IN SERIES THEREWITH TO PROVIDE A SPARK THEREAT WHEN SAID SECOND GAP IS INOPERABLE. 